| 摘要 |
PROBLEM TO BE SOLVED: To provide a power supply device wherein the number of parts is reduced to cut the cost and the size of a mounting board. SOLUTION: The power supply device includes: a flyback converter circuit 42 that has a transformer T1 whose a primary winding n1 is connected between the output terminals of a direct-current power supply circuit 41 through a switching element Q1 and a capacitor C1 to be charged with energy from a secondary winding n2 of the transformer T1 when the switching element Q1 is off and supplies a constant voltage to a load; a forward converter circuit 43 having a capacitor C2 charged with energy from a secondary winding n3 of the transformer T1 when the switching element Q1 is on; a control circuit 44 that turns on or off the switching element Q1 based on a feedback signal produced in the feedback winding n4 of the transformer T1; and a voltage conversion circuit 45 that switches the output voltage of the forward converter circuit 43 to generate an output voltage whose voltage value is variable and supplies it to another load. COPYRIGHT: (C)2009,JPO&INPIT
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